| # |
| # Building a vDSO image for AArch32. |
| # |
| # Author: Kevin Brodsky <kevin.brodsky@arm.com> |
| # A mix between the arm64 and arm vDSO Makefiles. |
| |
| ifeq ($(cc-name),clang) |
| CC_ARM32 := $(cc-name) $(CLANG_TARGET_ARM32) -no-integrated-as |
| GCC_ARM32_TC := $(realpath $(dir $(shell which $(CROSS_COMPILE_ARM32)ld))/..) |
| ifneq ($(GCC_ARM32_TC),) |
| CC_ARM32 += --gcc-toolchain=$(GCC_ARM32_TC) |
| endif |
| else |
| CC_ARM32 := $(CROSS_COMPILE_ARM32)$(cc-name) |
| endif |
| |
| # Same as cc-*option, but using CC_ARM32 instead of CC |
| cc32-option = $(call try-run,\ |
| $(CC_ARM32) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) |
| cc32-disable-warning = $(call try-run,\ |
| $(CC_ARM32) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) |
| cc32-ldoption = $(call try-run,\ |
| $(CC_ARM32) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2)) |
| |
| # We cannot use the global flags to compile the vDSO files, the main reason |
| # being that the 32-bit compiler may be older than the main (64-bit) compiler |
| # and therefore may not understand flags set using $(cc-option ...). Besides, |
| # arch-specific options should be taken from the arm Makefile instead of the |
| # arm64 one. |
| # As a result we set our own flags here. |
| |
| # From top-level Makefile |
| # NOSTDINC_FLAGS |
| VDSO_CPPFLAGS := -nostdinc -isystem $(shell $(CC_ARM32) -print-file-name=include) |
| VDSO_CPPFLAGS += $(LINUXINCLUDE) |
| VDSO_CPPFLAGS += -D__KERNEL__ |
| VDSO_CPPFLAGS += $(call cc-option,-Qunused-arguments,) |
| VDSO_CPPFLAGS += $(ARCH_CPPFLAGS) $(KCPPFLAGS) |
| |
| # Common C and assembly flags |
| # From top-level Makefile |
| VDSO_CAFLAGS := $(VDSO_CPPFLAGS) |
| VDSO_CAFLAGS += $(call cc32-option,-fno-PIE) |
| ifdef CONFIG_DEBUG_INFO |
| VDSO_CAFLAGS += -g |
| endif |
| ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC_ARM32)), y) |
| VDSO_CAFLAGS += -DCC_HAVE_ASM_GOTO |
| endif |
| |
| # From arm Makefile |
| VDSO_CAFLAGS += $(call cc32-option,-fno-dwarf2-cfi-asm) |
| VDSO_CAFLAGS += -mabi=aapcs-linux -mfloat-abi=soft |
| ifeq ($(CONFIG_CPU_BIG_ENDIAN), y) |
| VDSO_CAFLAGS += -mbig-endian |
| else |
| VDSO_CAFLAGS += -mlittle-endian |
| endif |
| |
| # From arm vDSO Makefile |
| VDSO_CAFLAGS += -fPIC -fno-builtin -fno-stack-protector |
| VDSO_CAFLAGS += -DDISABLE_BRANCH_PROFILING |
| |
| # Try to compile for ARMv8. If the compiler is too old and doesn't support it, |
| # fall back to v7. There is no easy way to check for what architecture the code |
| # is being compiled, so define a macro specifying that (see arch/arm/Makefile). |
| VDSO_CAFLAGS += $(call cc32-option,-march=armv8-a -D__LINUX_ARM_ARCH__=8,\ |
| -march=armv7-a -D__LINUX_ARM_ARCH__=7) |
| |
| VDSO_CFLAGS := $(VDSO_CAFLAGS) |
| # KBUILD_CFLAGS from top-level Makefile |
| VDSO_CFLAGS += -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ |
| -fno-strict-aliasing -fno-common \ |
| -Werror-implicit-function-declaration \ |
| -Wno-format-security \ |
| -std=gnu89 |
| VDSO_CFLAGS += -O2 |
| # Some useful compiler-dependent flags from top-level Makefile |
| VDSO_CFLAGS += $(call cc32-option,-Wdeclaration-after-statement,) |
| VDSO_CFLAGS += $(call cc32-option,-Wno-pointer-sign) |
| VDSO_CFLAGS += $(call cc32-option,-fno-strict-overflow) |
| VDSO_CFLAGS += $(call cc32-option,-Werror=strict-prototypes) |
| VDSO_CFLAGS += $(call cc32-option,-Werror=date-time) |
| VDSO_CFLAGS += $(call cc32-option,-Werror=incompatible-pointer-types) |
| |
| # The 32-bit compiler does not provide 128-bit integers, which are used in |
| # some headers that are indirectly included from the vDSO code. |
| # This hack makes the compiler happy and should trigger a warning/error if |
| # variables of such type are referenced. |
| VDSO_CFLAGS += -D__uint128_t='void*' |
| # Silence some warnings coming from headers that operate on long's |
| # (on GCC 4.8 or older, there is unfortunately no way to silence this warning) |
| VDSO_CFLAGS += $(call cc32-disable-warning,shift-count-overflow) |
| VDSO_CFLAGS += -Wno-int-to-pointer-cast |
| |
| VDSO_AFLAGS := $(VDSO_CAFLAGS) |
| VDSO_AFLAGS += -D__ASSEMBLY__ |
| |
| VDSO_LDFLAGS := $(VDSO_CPPFLAGS) |
| # From arm vDSO Makefile |
| VDSO_LDFLAGS += -Wl,-Bsymbolic -Wl,--no-undefined -Wl,-soname=linux-vdso.so.1 |
| VDSO_LDFLAGS += -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 |
| VDSO_LDFLAGS += -nostdlib -shared -mfloat-abi=soft |
| VDSO_LDFLAGS += $(call cc32-ldoption,-Wl$(comma)--hash-style=sysv) |
| VDSO_LDFLAGS += $(call cc32-ldoption,-Wl$(comma)--build-id) |
| VDSO_LDFLAGS += $(call cc32-ldoption,-fuse-ld=bfd) |
| |
| |
| # Borrow vdsomunge.c from the arm vDSO |
| # We have to use a relative path because scripts/Makefile.host prefixes |
| # $(hostprogs-y) with $(obj) |
| munge := ../../../arm/vdso/vdsomunge |
| hostprogs-y := $(munge) |
| |
| c-obj-vdso := vgettimeofday.o |
| asm-obj-vdso := sigreturn.o |
| |
| # Build rules |
| targets := $(c-obj-vdso) $(asm-obj-vdso) vdso.so vdso.so.dbg vdso.so.raw |
| c-obj-vdso := $(addprefix $(obj)/, $(c-obj-vdso)) |
| asm-obj-vdso := $(addprefix $(obj)/, $(asm-obj-vdso)) |
| obj-vdso := $(c-obj-vdso) $(asm-obj-vdso) |
| |
| obj-y += vdso.o |
| extra-y += vdso.lds |
| CPPFLAGS_vdso.lds += -P -C -U$(ARCH) |
| |
| # Force dependency (vdso.s includes vdso.so through incbin) |
| $(obj)/vdso.o: $(obj)/vdso.so |
| |
| include/generated/vdso32-offsets.h: $(obj)/vdso.so.dbg FORCE |
| $(call if_changed,vdsosym) |
| |
| # Strip rule for vdso.so |
| $(obj)/vdso.so: OBJCOPYFLAGS := -S |
| $(obj)/vdso.so: $(obj)/vdso.so.dbg FORCE |
| $(call if_changed,objcopy) |
| |
| $(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/$(munge) FORCE |
| $(call if_changed,vdsomunge) |
| |
| # Link rule for the .so file, .lds has to be first |
| $(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE |
| $(call if_changed,vdsold) |
| |
| # Compilation rules for the vDSO sources |
| $(filter-out vgettimeofday.o, $(c-obj-vdso)): %.o: %.c FORCE |
| $(call if_changed_dep,vdsocc) |
| $(asm-obj-vdso): %.o: %.S FORCE |
| $(call if_changed_dep,vdsoas) |
| |
| # Actual build commands |
| quiet_cmd_vdsold = VDSOL32 $@ |
| cmd_vdsold = $(CC_ARM32) -Wp,-MD,$(depfile) $(VDSO_LDFLAGS) \ |
| -Wl,-T $(filter %.lds,$^) $(filter %.o,$^) -o $@ |
| quiet_cmd_vdsocc = VDSOC32 $@ |
| cmd_vdsocc = $(CC_ARM32) -Wp,-MD,$(depfile) $(VDSO_CFLAGS) -c -o $@ $< |
| quiet_cmd_vdsoas = VDSOA32 $@ |
| cmd_vdsoas = $(CC_ARM32) -Wp,-MD,$(depfile) $(VDSO_AFLAGS) -c -o $@ $< |
| |
| quiet_cmd_vdsomunge = MUNGE $@ |
| cmd_vdsomunge = $(obj)/$(munge) $< $@ |
| |
| # Generate vDSO offsets using helper script (borrowed from the 64-bit vDSO) |
| gen-vdsosym := $(srctree)/$(src)/../vdso/gen_vdso_offsets.sh |
| quiet_cmd_vdsosym = VDSOSYM $@ |
| # The AArch64 nm should be able to read an AArch32 binary |
| cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ |
| |
| # Install commands for the unstripped file |
| quiet_cmd_vdso_install = INSTALL $@ |
| cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/vdso32.so |
| |
| vdso.so: $(obj)/vdso.so.dbg |
| @mkdir -p $(MODLIB)/vdso |
| $(call cmd,vdso_install) |
| |
| vdso_install: vdso.so |
